Automobile drivers know that finding an open parking space can be extremely difficult at times. For example, in urban areas, open parking—whether at meters, in open lots, or in ramps—can be rare and fleeting, particularly right before a major event such as a ball game. The simultaneous presence of an open parking spot and a person looking for parking but who does not know about the spot, is a true dead weight loss—the user wastes time looking, and the parking operator loses revenue.
Parking operators have tried various techniques to advertise the fact that they have open parking spaces. For example, neon signs may be posted at lots or ramps to indicate that there are open spaces or that there are no open spaces. Also, ramp or lot operators may post information and make it available over the internet to indicate whether parking is available at certain locations.